Piston expander



vFiled March 29, 1957 f/ mw Q WE O Z VH W mi 0 A .HV wxw HM. E f L M W 6 R n J` IPatented Feb. 20, 1940 PISTON EXPANDER William H. Wheeler, Denver, Colo., assignor to Francis J. Casey, Denver, Colo.

Application March 29, 1937, Serial No. 133,624

8 Claims.

ternal combustion motors as used in automobiles and the like and to a device for accomplishing such expansion in accordance with such method.

An object of the invention is to provide `a method and device for expanding pistons in accordance with which and by means of which pressure is exerted concidently upon the outer and inner surfaces of the piston Wall at any desired point and in degree sufcient to compress, and thereby lessen the thickness of the wall at such point, resulting in a corresponding expansion of the periphery of the piston at such point.

A further object is to provide a method and apparatus for applying pressure, rollingly and coincidently to the outer and inner surfaces of the piston wall at any desired point thereof.

A further object is to provide a device of the class described which is, in size, a small tool, operable by hand to full efficiency, and in which there is combined, with the above features, simplicity of construction and operation, strength, durability and great economy as to both construction and operation.

With these and other objects in view, as will more fully hereinafter appear, my invention comprises certain novel steps, operations, constructicns, combinations and arrangements of parts as will now be described and claimed and as illustrated in the accompanying drawing, in which there is illustrated a preferred embodiment of my invention of an apparatus for practicing my said method and in which drawing Figure 1 is a side elevation of my expander.

Figure 2 is a vertical, longitudinal section of the expander taken centrally thereof, as upon line 2--2 of Figure 3, but showing certain parts in full lines.

Figure 3 is a fragmentary section on line 3-3 of Fig. 1.

In course of use, pistons and the cylinders in which they operate lose their `normal exact sliding interrelation. Through wear or other causes the inner cylinder wall or the outer piston wall or both become distorted fromthe normal, resulting in looseness piston slap and other undesired results.

The expansion of the outer wall of the piston at the proper point or points will reestablish substantially the normal exact sliding interrelation of piston and cylinder.

Various methods `and `devices for accomplishing such expansion and for limiting the same to the desired degree and extent in area have been used but have been found subject to some or all of the. objections of expense, bulk, clumsiness, lack of `exact control, difliculty in operation and general inefciency. i

I have found that from compression of the piston wall, expansion of the periphery results. Excessive compression at any one point would, however, result in bulging `the wall adjacent such point of compression instead of evenly expand- 10 ing the desired area.

It is necessary, therefore, to have exact control of the degree of pressure exerted and, likewise, to move the point of application of pressure throughout the area to be expanded while retaining such control. I have found that by the application of pressure on inner and outer surfaces of the piston wall at opposed points and applying such pressure rollingly, the piston wall may be compressed to the desired degree,

throughout the desired area resulting in the expansion of the outer surface of the piston wall Within such area and to the degree necessary to take up the looseness and substantially reestablish the exact sliding fit between the piston and the cylinder.

As a means of operating in accordance with my said method, I have provided the device illustrated in the drawing comprising a suitable base l, adapted to be fastened to a table or, preferably, gripped in an ordinary vise. On one end the base carries a split support 2 between the upper ends of which ispivotallyvmounted, as by pivot screws 3, a barrel 4 carrying a shaft 5 centrally, longitudinally and rotatably therein.` At its forward end the shaft 5 carries a knurled wheel 6 which may be formed integral with shaft 5. At its `rear end shaft 5 is provided with a handle i securely affixed thereto by any suitable means. A tapered t indicated at 3, se- 49 cured by nut 9 has been found sufficient.

Approximately midway of the barrel I provide a yoke Ill, carried by base l and enclosing barrel fl, the sides of the yoke being spaced to permit vertical movement of the barrel d therebetween. Within the yoke lll` beneath barrel il I provide coiled spring I l for normally forcing barrel 4 upwardly and in the top of the yoke I provide a threaded shaft l2 having handle i3 for forcing the barrel downwardly against the pres- 50 sure of spring Il.

Beneath knurled wheel 5 I provide aroller lll rotatably mounted bymeans ofA trunnions ,i5 in notched standards I6. On both sides of `roller I4 the base is raised as at il whereby to provide, 55 

